One in three of us will develop cancer during our lifetime. This incidence will increase as the population ages. Advances in medical knowledge have lead to an exponential increase in healthcare options for the prevention, diagnosis and therapy of cancer. Choices among competing alternatives are often difficult because the available evidence may differ among options, and may not reflect values that are important to patients when making healthcare decisions. There is increasing recognition that patient preferences are instrumental in making appropriate decisions for care. Many studies are based on biomedical outcomes that are not easily understood by patients, and often, not well understood either by clinicians or policy-makers. Comparative effectiveness research (CER) aims to inform healthcare decisions by providing evidence on the benefits and harms of different alternatives. CER synthesizes and generates comparable evidence on the effectiveness of interventions so that decision-makers (patients, clinicians and policy-makers) can make informed choices. Patient-centered outcomes research (PCOR) ensures that the evidence gathered through CER is relevant to patients and provides information on outcomes that people care about: survival, symptoms, function and quality of life. This is especially important for patients with cancer since therapies can be effective for some outcomes (e.g. disease- free survival) but deleterious for others (e.g. quality of life affected by treatment toxicity). As CER/PCOR evolves there is increased need for training researchers in this area. For this proposal we have partnered with the American Society of Clinical Oncology (ASCO) to offer training and workforce development opportunities in the field of CER/PCOR in cancer care. The goal of this application is to provide a comprehensive training program for cancer researchers interested in CER/PCOR. We have identified four major interrelated methodology cores for training: (i) Knowledge synthesis and translation; (ii) Observational research and registries; (iii Pragmatic clinical trials and healthcare delivery evaluation; and (iv) Patient-centered outcomes research. Our program will provide different levels of training. Basic learning modules will be implemented through on-demand online lectures and interactive components (Q&A online sessions and methods blog). Advanced methods training will be offered in partnership with ASCO and will include Webinars and hands-on face-to-face educational workshops. Finally, on-site experiential learning for fellows will be provided with specialization in one of the core area identified above. This component will also include a personalized mentoring plan. Our training program will encompass the whole spectrum of cancer care including prevention, cancer treatment and healthcare delivery, supportive care, survivorship, and end-of-life care. The proposed program is unique in the field of cancer research, it will provide innovative peer-to-peer learning opportunities, and will enhance best research practices. The training proposed here will increase the nation's workforce of researchers conducting state-of-the-art CER/PCOR throughout the spectrum of cancer care.